3 questions · 3 marks · ≈ 3 min
The temperature of a thermistor is increased.
Which row in the table identifies the effect of the temperature increase on the number of conduction electrons and the amplitude of lattice vibrations?
| Number of conduction electrons | Amplitude of lattice vibrations | |
|---|---|---|
| A | increases | increases |
| B | decreases | increases |
| C | increases | stays the same |
| D | decreases | stays the same |
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The diagram shows a cell of e.m.f. ε and internal resistance r. The cell is connected in series with two resistors of resistance R1 and R2. The potential difference across R1 is V1. The current in the circuit is I.
Which of the following expressions is correct?
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ε = V1 + Ir
ε = IR1 + Ir
ε = IR2 + Ir
ε = V1 + IR2 + Ir
As temperature increases, the resistance of a negative temperature coefficient thermistor changes.
Which of the following describes the reason for this change?
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Collisions between electrons and ions occur less frequently.
More conduction electrons are released.
The ions in the thermistor vibrate less.
The ions in the thermistor vibrate more.